Tie bars or couplings having a pair of end bushings connected by a wire-wound polyurethane impregnated endless belt are well known as evidenced by U.S. Pat. No. 3,782,220 issued Jan. 1, 1974 to R. J. Ditlinger (common assignee). The present invention represents an improvement over the tie bar of U.S. Pat. No. 3,782,220.
It has been found that the wires in the prior art tie bars of U.S. Pat. No. 3,782,220 are subject to uneven stress during twisting motion about the longitudinal axis of the tie bar which uneven stress results from the spacing variations of the wires relative to the longitudinal axis of the tie bar with the outermost or edge wires being farthest from the axis thereby having the greatest stress. It will be recognized that the ideal solution would be to have all wires equally stressed under a maximum twist condition of the tie bar. However, the ideal solution is not economically feasible and alternative more practical solutions must be resorted to. To that end, the present invention proposes modification of the clip structure only of the tie bar to effect a stress reduction in the highly stressed outer or edge wires.